.. Feather head crests have been found in fossils of some dinosaurs and early birds as well as a wide variety of living species of birds. While feather crests have usually been studied for their roles as possible visual signals, recent behavioral studies of two auklet species have shown that their erect head crest feathers can play a mechanosensory role during tactile navigation similar to that of mammalian whiskers and arthropod antennae. These findings suggest that feather crests in other birds also might play a previously unrecognized mechanosensory functional role. ...
https://www.researchgate.net/figure/Artificial-white-crest-worn-by-male-long-tailed-finch-left-and-male-zebra-finch_fig2_23276464

"A Taste for the Beautiful" Latent Aesthetic Mate Preferences ...

''Darwin first hypothesized that bright colors and elaborate ornamentation of male animals evolved in response to the "aesthetic" mate preferences of females.''



Artificial white crest worn by male long-tailed finch ( left ) and male zebra finch ( right ) during mate choice trials. Photo credit: Kerry Clayman.

https://www.researchgate.net/figure/Artificial-white-crest-worn-by-male-long-tailed-finch-left-and-male-zebra-finch_fig2_23276464